Tubular oil converter



y 1933. IIM. B. CHITTICK 1,910,242

TUBULAR OIL CONVERTER Filed June 19, 1950 6 w Mara flc/zimfck ahbmq Patented May 23, 1933 UNITED MARTIN B. CHITTICK, OI CHICAGO, ILLINOIS, ASSIGNOR TO PURE OIL COMPANY, OF.

CHICAGO, ILLINOIS, A CORPORATION OF OHIO i i I PATENT era-i:

TUBULAR OIL CONVERTER Application filed June 19,

' jected to high temperatures to effect their molecular decomposition.

It is a common practice to pass vaporized oils in an elongated stream of restricted cross-section through the tubular passes,

" banks or coils of an oil heater wherein the oils are brought to crack ng temperatures.

which are frequently in excess of 1000 F. The oil vapors in passing through the externally heated pipes or tubes of such apparatus contact with the heated walls while traveling at high velocity so that heat exchange takes place, the temperature of the tube walls and the velocity of the vapors having an important bearing on the rate of Q0 heat transfer. It has been observedthat in high temperature oil cracking heaters wherein oil in the vapor phase is heated to conversion temperatures, for example, between 1000 F. and 1200 F., not only are low boiling point oils of gasoline range produced from higher boiling oils, but in addition there are also produced large quantities of fixed gas and free carbon, the gas being discharged from the heaters witlrtlie cracked vaporized products while the carbontends, atleast, in part, to produce a hardened encrustation or coating onthe inner wallsof the heater tubes which interferes with the heating efficiency of such tubes and, also, results in relatively short life thereof.

This condition is though to be due to the fact that while the oil vapor is, passing through a highly heated tube the annular film or strata of the oil vapor 'nearestor in 0 contact with the inner wall of the tube is overheated. That is to say, that portion of the oil vapor which contacts directly with the highly heated surfaces of the heater tubes attains a temperature considerably above the desired average or mean cracking temperature, with the result that this portion of the oil vapor is overly heated producing therein violent splitting or decomposition reactions which produce the fixed or permanent gas and carbon deposition. Oil

.ing temperature, the fundamentalobjections 1930. Serial No; 462,361.

is a relatively poor. conductor for heat and as a result the oil in the center or axial portion of the vapor stream passing through he heater tubes is, in fact, underheated in-v sofar as a desired cracking temperature is; concerned. This condition results in a low rate ot'cracking of the oil vapor for each. passage of the latter through the heater, witl the result that large quantities of re cycle stock are produced which must be again passed through theheater for additional'treatmenta To improve this condition it has been proposed heretofore to provide oil converters with tubes of relatively small diameter in order to provide but small volumes ofoil vapor in any one of such tubes in comparison with the heating surface present .Small tubes, however, lead to mechanical. difficule ties, particularly in high temperature apparatus wherein furnace temperatures "of the order of 1500 to 2000 F. are employed. It 7 has also been-suggested to employ tubes of larger diameter which are capable. of with standing the severe furnace temperatures. without rapid deterioration and to provide the interiorsoi such tubes with longitudinally extending cores which restrict the internal cross-sectional area of the tubes, which provide higher vapor'velocities and limit the; vapor in any one tube.

Whilethese expediencies have improved to some degree the heating of oil vapor in a more uniform manner to a desired crack- "abovenoted with respect to lack of uniformity of heating the. entire'mass of oil vapor passing through the tubes still obtains, with the result that carbon deposition persists in the converter tubes and fixed'gas formation is unduly high.

i The present invention provides for the more uniform heating of the oil vapor passing through an externally heated tubular converter (or oil heater) by providing the tubes of such converters with longitudinally extending cores consisting of helical metallic strips which are so shaped andproportioned that as the" oil or oil vapor passes longitudinally through the tubes equipped with. such 19 yes strips or cores, the fluid undergoing heating, in conforming to the shape of the cores, is given a swirling, helical or rotary motion producing suflicient turbulence of flow to bring all portions of such fluid into contact with the heated walls 'of the tubes, whereby such fluid is uniformly heated to desired temperatures and, specifically, under or over heating of various portions or fractions of the fluid is avoided.

It is another object of the invention't-o provide the helically bent strips .or cores with outwardly projecting lugs or prongs, which engage with the inner walls. ofthe header tubes in which such cores are positioned in order to positively retain the cores in desired operating positions within the tubes andto prevent accidental displacement thereof.

It is a further object of the'invention to provide the helieally bent stripsor cores with operating stems which terminate in actuating portions disposed exteriorly of the header and whereby through the provision of such actuating portions the cores may be rotated axially within the tubes in which they are operatively positioned or moved longitudinally of such tubes to obtain desired operating positions on the part thereof while the heater is in operation.

For a further understanding of the in vention reference is to be had to the following description and to the accompanying drawing, wherein:

Figure 1 is a vertical longitudinal sectional view taken through one of the tubes of an oil converter provided with a helical core formed in accordance with the present invention, 7

Figure 2 is a transverse sectional View taken on the line 22 of Figure 1,

Figure 3 is a front elevation of the actuating portion of the core, and

Figure .4 is a detail perspective view of the core removed from the header.

Referring more particularlyto thedrawing, the numeral 1 designates a tube of the type used in connection with oil heaters or converters. These tubes are'usually mounted within the masonry wall structure of a furnace (not shown) and ordinarily the "tube is formed from ferrous alloys which permit the walls thereof to successfully withstand relatively high furnace temperatures for extended periods of operation without mechanical failure. These tubes are frequently formed from chromium containing ferrous alloys or other oxidation resisting metals or, again, ordinary steel tubes are especially treated to'enable them to more successfully resist the deleterous action of high temperature furnace gases. In low temperature oil heaters ordinary mild steel tubes may be used: Oils or oil vapors are passed longi- H tudinally through the tube 1 whenthe latter vapor and the heated walls of the tube 1,

the latter is provided with an axially disposed longitudinally extending core 2. In the specific form of the invention herein disclosed the core consists of a flat metallic strip bent longitudinally and axially into helical form, comprising a plurality of merged helical surfaces of considerable pitch. In the industry,-these cores are referred to as helical, and sometimes spiral, bars or strips. Spurs or prongs 3 are struck fromor welded to the cores at spaced longitudinal intervals and are so disposed as to engage with the inner walls of said tubes to maintain the cores in their fixed positions of application within the tubes, specific-ally avoiding accidental displacement of the cores while the oil heater is in operation.

The tube 1 is connected at one endwith a header 4 to which oil vapor is supplied from any suitable source. In alignment with the tube 1; the header has its front Wall provid'edwith an opening 5 which is normally closed by means of a key plug6 securely held in place by means of threaded positioning elements 7 The key plug carries a rigidly connected stuffing box 8 which receives a stem 9 projecting axially and for- Wardly from each core2. Exterior-l7; of the header and of the oil heater each stem 9 provided with an operating handle 10 which may be manually actuate-d in order to secure circular rotary movement of each core or .1.

the longitudinal adjustment thereofwithin its supporting tube. These adjustments may be obtained without interferring with the active operation of the heater.

By the employment of the construction.

disclosed the oil, vapor passing from the headerthrough the tube 1 contacts with the helical surfaces of the core 2 and is given a rapid swirling turbulent flow while passing longitudinally through the tube. This brings all portions ofthe 'oil vapor into contact with the'highly heated surfacesof said tube (ortub'es) so that such oil vapor is uniformly heated to a desired operating temperature. heating or overheating of various fractions of th e oil vapor are eliminated and high yields of desired compounds obtained.

- What is claimed is z" L'In apparatus ,for heating oil in the vapor phase,"a tube, a core consisting of a Thus the evils due to underhelically twisted metallic bar arranged longitudinally in the tube, and an operating stem connected with one end of said core and having an operating portion arranged exteriorly of the cracking apparatus for adjusting said core rotatably andlongitudinally within said tube. V

2. In an oil converter, a header, a tube connected with said header and in open com munication with the interior thereof, a helical core positioned longitudinally within said tube, and an operating stem connected with one end of said core and terminating exteriorly of said header to provide forrotary and longitudinal adjustment of the core within said tube during the active operation of the converter.

In an oil converter, a header, a tube connected with one of the walls of said header and arranged in registration with an opening formed in the opposite wall of the header, a key plug normally closing said latter opening, a helical core arranged in said tube, and an operating stem connected with said core and inovably supported by said key plug, said stem terminating in an operating portion arranged exteriorly of the header to provide for the rotary and longitudinal adjustment of the core within said tube.

4:. In apparatus for cracking oil in the vapor phase, an externally heated tube, a helically twisted metallic bar positioned longitudinally within said tube and spaced substantially from the inner walls of said tube and a plurality of longitudinally spaced po sitioning spurs projecting laterally from the edge portions of said bar and contacting with the inner walls of said tube to maintain said bar in an axial position Within the tube with the edge portions of said bar spaced from the inner walls of the tube.

In testimony whereof I aflix my signature.

MARTIN B. CHITTICK. 

